public class test {
    public static void main1(String[] args) {
        //判定素数
        int n = 0;
        int i = 0;
        for(i = 2;i < n;i++) {
            if(n % i == 0) {
                break;
            }
        }
        if(i >= n){
            System.out.println("This is a prime:" + n);
        }
        else{
            System.out.println("This is not a prime!");
        }
    }

    public static void main2(String[] args) {
        int n = 0;
        for(n = 1; n <= 100;n++) {
            int i = 0;
            for(i = 2;i < n;i++) {
                if(n % i == 0) {
                    break;
                }
            }
            /*if(i >= n){
                System.out.println("This is a prime:" + n);
            }
            else{
                System.out.println("This is not a prime!");
            }*/
            if(i >= n) {
                System.out.println("This is a prime:" + n);
            }
        }
    }

    public static void main3(String[] args) {
        int year = 0;
        for(year = 1000;year <= 2000;year++){
            //判断闰年
            if((year % 400 == 0)||((year % 4 == 0)&&(year %100 != 0))){
                System.out.print(year + " ");
            }
        }
    }

    public static void main(String[] args) {
        int i = 1;
        int count = 0;
        for(i = 1;i <= 100;i++){
            if(i / 10 == 9){
                count++;
            }
            if(i % 10 == 9){
                count++;
            }
        }
        System.out.println(count);
    }
}
